diff --git a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/CommandScheduler.java b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/CommandScheduler.java
index b869f4e086..4c87c66e25 100644
--- a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/CommandScheduler.java
+++ b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/CommandScheduler.java
@@ -585,7 +585,7 @@ public final class CommandScheduler implements Sendable, AutoCloseable {
    */
   public void registerComposedCommands(Command... commands) {
     var commandSet = Set.of(commands);
-    requireNotComposed(commandSet);
+    requireNotComposedOrScheduled(commandSet);
     var exception = new Exception("Originally composed at:");
     exception.fillInStackTrace();
     for (var command : commands) {
@@ -617,7 +617,7 @@ public final class CommandScheduler implements Sendable, AutoCloseable {
   }
 
   /**
-   * Requires that the specified command hasn't been already added to a composition.
+   * Requires that the specified command hasn't already been added to a composition.
    *
    * @param commands The commands to check
    * @throws IllegalArgumentException if the given commands have already been composed.
@@ -635,7 +635,7 @@ public final class CommandScheduler implements Sendable, AutoCloseable {
   }
 
   /**
-   * Requires that the specified commands not have been already added to a composition.
+   * Requires that the specified commands have not already been added to a composition.
    *
    * @param commands The commands to check
    * @throws IllegalArgumentException if the given commands have already been composed.
@@ -644,6 +644,34 @@ public final class CommandScheduler implements Sendable, AutoCloseable {
     requireNotComposed(commands.toArray(Command[]::new));
   }
 
+  /**
+   * Requires that the specified command hasn't already been added to a composition, and is not
+   * currently scheduled.
+   *
+   * @param command The command to check
+   * @throws IllegalArgumentException if the given command has already been composed or scheduled.
+   */
+  public void requireNotComposedOrScheduled(Command command) {
+    if (isScheduled(command)) {
+      throw new IllegalArgumentException(
+          "Commands that have been scheduled individually may not be added to a composition!");
+    }
+    requireNotComposed(command);
+  }
+
+  /**
+   * Requires that the specified commands have not already been added to a composition, and are not
+   * currently scheduled.
+   *
+   * @param commands The commands to check
+   * @throws IllegalArgumentException if the given commands have already been composed or scheduled.
+   */
+  public void requireNotComposedOrScheduled(Collection<Command> commands) {
+    for (var command : commands) {
+      requireNotComposedOrScheduled(command);
+    }
+  }
+
   /**
    * Check if the given command has been composed.
    *
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/CommandScheduler.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/CommandScheduler.cpp
index 63d1e3bf14..efeee4e644 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/CommandScheduler.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/CommandScheduler.cpp
@@ -477,6 +477,29 @@ void CommandScheduler::RequireUngrouped(
   }
 }
 
+void CommandScheduler::RequireUngroupedAndUnscheduled(const Command* command) {
+  if (IsScheduled(command)) {
+    throw FRC_MakeError(frc::err::CommandIllegalUse,
+                        "Commands that have been scheduled individually may "
+                        "not be added to another composition!");
+  }
+  RequireUngrouped(command);
+}
+
+void CommandScheduler::RequireUngroupedAndUnscheduled(
+    std::span<const std::unique_ptr<Command>> commands) {
+  for (auto&& command : commands) {
+    RequireUngroupedAndUnscheduled(command.get());
+  }
+}
+
+void CommandScheduler::RequireUngroupedAndUnscheduled(
+    std::initializer_list<const Command*> commands) {
+  for (auto&& command : commands) {
+    RequireUngroupedAndUnscheduled(command);
+  }
+}
+
 void CommandScheduler::InitSendable(wpi::SendableBuilder& builder) {
   builder.SetSmartDashboardType("Scheduler");
   builder.AddStringArrayProperty(
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/ConditionalCommand.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/ConditionalCommand.cpp
index 4c07c7ae24..6ce33b7548 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/ConditionalCommand.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/ConditionalCommand.cpp
@@ -12,7 +12,7 @@ ConditionalCommand::ConditionalCommand(std::unique_ptr<Command>&& onTrue,
                                        std::unique_ptr<Command>&& onFalse,
                                        std::function<bool()> condition)
     : m_condition{std::move(condition)} {
-  CommandScheduler::GetInstance().RequireUngrouped(
+  CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(
       {onTrue.get(), onFalse.get()});
 
   m_onTrue = std::move(onTrue);
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelCommandGroup.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelCommandGroup.cpp
index 99e0845c8d..4a234b1475 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelCommandGroup.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelCommandGroup.cpp
@@ -63,7 +63,7 @@ Command::InterruptionBehavior ParallelCommandGroup::GetInterruptionBehavior()
 
 void ParallelCommandGroup::AddCommands(
     std::vector<std::unique_ptr<Command>>&& commands) {
-  CommandScheduler::GetInstance().RequireUngrouped(commands);
+  CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(commands);
 
   if (isRunning) {
     throw FRC_MakeError(frc::err::CommandIllegalUse,
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelDeadlineGroup.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelDeadlineGroup.cpp
index a6b5c1c264..1c9b700534 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelDeadlineGroup.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelDeadlineGroup.cpp
@@ -62,7 +62,7 @@ Command::InterruptionBehavior ParallelDeadlineGroup::GetInterruptionBehavior()
 
 void ParallelDeadlineGroup::AddCommands(
     std::vector<std::unique_ptr<Command>>&& commands) {
-  CommandScheduler::GetInstance().RequireUngrouped(commands);
+  CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(commands);
 
   if (!m_finished) {
     throw FRC_MakeError(frc::err::CommandIllegalUse,
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelRaceGroup.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelRaceGroup.cpp
index df658bcc73..334286f8e3 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelRaceGroup.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/ParallelRaceGroup.cpp
@@ -50,7 +50,7 @@ Command::InterruptionBehavior ParallelRaceGroup::GetInterruptionBehavior()
 
 void ParallelRaceGroup::AddCommands(
     std::vector<std::unique_ptr<Command>>&& commands) {
-  CommandScheduler::GetInstance().RequireUngrouped(commands);
+  CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(commands);
 
   if (isRunning) {
     throw FRC_MakeError(frc::err::CommandIllegalUse,
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/RepeatCommand.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/RepeatCommand.cpp
index 2e74c8c72f..2a08f1b043 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/RepeatCommand.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/RepeatCommand.cpp
@@ -9,7 +9,7 @@
 using namespace frc2;
 
 RepeatCommand::RepeatCommand(std::unique_ptr<Command>&& command) {
-  CommandScheduler::GetInstance().RequireUngrouped(command.get());
+  CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(command.get());
   m_command = std::move(command);
   m_command->SetComposed(true);
   AddRequirements(m_command->GetRequirements());
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/SequentialCommandGroup.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/SequentialCommandGroup.cpp
index b9ea3d56ec..173b9d93c8 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/SequentialCommandGroup.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/SequentialCommandGroup.cpp
@@ -62,7 +62,7 @@ Command::InterruptionBehavior SequentialCommandGroup::GetInterruptionBehavior()
 
 void SequentialCommandGroup::AddCommands(
     std::vector<std::unique_ptr<Command>>&& commands) {
-  CommandScheduler::GetInstance().RequireUngrouped(commands);
+  CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(commands);
 
   if (m_currentCommandIndex != invalid_index) {
     throw FRC_MakeError(frc::err::CommandIllegalUse,
diff --git a/wpilibNewCommands/src/main/native/cpp/frc2/command/WrapperCommand.cpp b/wpilibNewCommands/src/main/native/cpp/frc2/command/WrapperCommand.cpp
index f7928c964e..6391294f30 100644
--- a/wpilibNewCommands/src/main/native/cpp/frc2/command/WrapperCommand.cpp
+++ b/wpilibNewCommands/src/main/native/cpp/frc2/command/WrapperCommand.cpp
@@ -9,7 +9,7 @@
 using namespace frc2;
 
 WrapperCommand::WrapperCommand(std::unique_ptr<Command>&& command) {
-  CommandScheduler::GetInstance().RequireUngrouped(command.get());
+  CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(command.get());
   m_command = std::move(command);
   m_command->SetComposed(true);
   // copy the wrapped command's name
diff --git a/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h b/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h
index ce4dc914c2..1f8d74297a 100644
--- a/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h
+++ b/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h
@@ -374,7 +374,7 @@ class CommandScheduler final : public wpi::Sendable,
   void OnCommandFinish(Action action);
 
   /**
-   * Requires that the specified command hasn't been already added to a
+   * Requires that the specified command hasn't already been added to a
    * composition.
    *
    * @param command The command to check
@@ -383,7 +383,7 @@ class CommandScheduler final : public wpi::Sendable,
   void RequireUngrouped(const Command* command);
 
   /**
-   * Requires that the specified commands not have been already added to a
+   * Requires that the specified commands have not already been added to a
    * composition.
    *
    * @param commands The commands to check
@@ -392,7 +392,7 @@ class CommandScheduler final : public wpi::Sendable,
   void RequireUngrouped(std::span<const std::unique_ptr<Command>> commands);
 
   /**
-   * Requires that the specified commands not have been already added to a
+   * Requires that the specified commands have not already been added to a
    * composition.
    *
    * @param commands The commands to check
@@ -401,6 +401,38 @@ class CommandScheduler final : public wpi::Sendable,
    */
   void RequireUngrouped(std::initializer_list<const Command*> commands);
 
+  /**
+   * Requires that the specified command has not already been added to a
+   * composition and is not currently scheduled.
+   *
+   * @param command The command to check
+   * @throws IllegalArgumentException if the given command has already been
+   * composed or scheduled.
+   */
+  void RequireUngroupedAndUnscheduled(const Command* command);
+
+  /**
+   * Requires that the specified commands have not already been added to a
+   * composition and are not currently scheduled.
+   *
+   * @param commands The commands to check
+   * @throws IllegalArgumentException if the given commands have already been
+   * composed.
+   */
+  void RequireUngroupedAndUnscheduled(
+      std::span<const std::unique_ptr<Command>> commands);
+
+  /**
+   * Requires that the specified commands have not already been added to a
+   * composition and are not currently scheduled.
+   *
+   * @param commands The commands to check
+   * @throws IllegalArgumentException if the given commands have already been
+   * composed or scheduled.
+   */
+  void RequireUngroupedAndUnscheduled(
+      std::initializer_list<const Command*> commands);
+
   void InitSendable(wpi::SendableBuilder& builder) override;
 
  private:
diff --git a/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h b/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h
index d425d76c56..4c2ba66fde 100644
--- a/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h
+++ b/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h
@@ -56,7 +56,8 @@ class SelectCommand : public CommandHelper<Command, SelectCommand<Key>> {
 
     m_defaultCommand.SetComposed(true);
     for (auto&& command : foo) {
-      CommandScheduler::GetInstance().RequireUngrouped(command.second.get());
+      CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(
+          command.second.get());
       command.second.get()->SetComposed(true);
     }
 
@@ -77,7 +78,8 @@ class SelectCommand : public CommandHelper<Command, SelectCommand<Key>> {
       : m_selector{std::move(selector)} {
     m_defaultCommand.SetComposed(true);
     for (auto&& command : commands) {
-      CommandScheduler::GetInstance().RequireUngrouped(command.second.get());
+      CommandScheduler::GetInstance().RequireUngroupedAndUnscheduled(
+          command.second.get());
       command.second.get()->SetComposed(true);
     }
 
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/CommandGroupErrorTest.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/CommandGroupErrorTest.java
deleted file mode 100644
index ba4a77b829..0000000000
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/CommandGroupErrorTest.java
+++ /dev/null
@@ -1,47 +0,0 @@
-// Copyright (c) FIRST and other WPILib contributors.
-// Open Source Software; you can modify and/or share it under the terms of
-// the WPILib BSD license file in the root directory of this project.
-
-package edu.wpi.first.wpilibj2.command;
-
-import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-import org.junit.jupiter.api.Test;
-
-class CommandGroupErrorTest extends CommandTestBase {
-  @Test
-  void commandInMultipleGroupsTest() {
-    MockCommandHolder command1Holder = new MockCommandHolder(true);
-    Command command1 = command1Holder.getMock();
-    MockCommandHolder command2Holder = new MockCommandHolder(true);
-    Command command2 = command2Holder.getMock();
-
-    new ParallelCommandGroup(command1, command2);
-    assertThrows(
-        IllegalArgumentException.class, () -> new ParallelCommandGroup(command1, command2));
-  }
-
-  @Test
-  void commandInGroupExternallyScheduledTest() {
-    MockCommandHolder command1Holder = new MockCommandHolder(true);
-    Command command1 = command1Holder.getMock();
-    MockCommandHolder command2Holder = new MockCommandHolder(true);
-    Command command2 = command2Holder.getMock();
-
-    new ParallelCommandGroup(command1, command2);
-
-    assertThrows(
-        IllegalArgumentException.class, () -> CommandScheduler.getInstance().schedule(command1));
-  }
-
-  @Test
-  void redecoratedCommandErrorTest() {
-    Command command = new InstantCommand();
-
-    assertDoesNotThrow(() -> command.withTimeout(10).until(() -> false));
-    assertThrows(IllegalArgumentException.class, () -> command.withTimeout(10));
-    CommandScheduler.getInstance().removeComposedCommand(command);
-    assertDoesNotThrow(() -> command.withTimeout(10));
-  }
-}
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/MultiCompositionTestBase.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/MultiCompositionTestBase.java
index 2b79550cb7..46cb03cd9a 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/MultiCompositionTestBase.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/MultiCompositionTestBase.java
@@ -13,11 +13,11 @@ import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
-interface MultiCompositionTestBase<T extends Command> extends SingleCompositionTestBase<T> {
-  T compose(Command... members);
+abstract class MultiCompositionTestBase<T extends Command> extends SingleCompositionTestBase<T> {
+  abstract T compose(Command... members);
 
   @Override
-  default T composeSingle(Command member) {
+  T composeSingle(Command member) {
     return compose(member);
   }
 
@@ -63,7 +63,7 @@ interface MultiCompositionTestBase<T extends Command> extends SingleCompositionT
 
   @MethodSource
   @ParameterizedTest(name = "interruptible[{index}]: {0}")
-  default void interruptible(
+  void interruptible(
       @SuppressWarnings("unused") String name,
       InterruptionBehavior expected,
       Command command1,
@@ -103,7 +103,7 @@ interface MultiCompositionTestBase<T extends Command> extends SingleCompositionT
 
   @MethodSource
   @ParameterizedTest(name = "runsWhenDisabled[{index}]: {0}")
-  default void runsWhenDisabled(
+  void runsWhenDisabled(
       @SuppressWarnings("unused") String name,
       boolean expected,
       Command command1,
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroupTest.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroupTest.java
index 7dc91106ee..a837baac8a 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroupTest.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroupTest.java
@@ -14,8 +14,7 @@ import static org.mockito.Mockito.verify;
 
 import org.junit.jupiter.api.Test;
 
-class ParallelCommandGroupTest extends CommandTestBase
-    implements MultiCompositionTestBase<ParallelCommandGroup> {
+class ParallelCommandGroupTest extends MultiCompositionTestBase<ParallelCommandGroup> {
   @Test
   void parallelGroupScheduleTest() {
     try (CommandScheduler scheduler = new CommandScheduler()) {
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroupTest.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroupTest.java
index 6fa644bb24..789827bf6c 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroupTest.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroupTest.java
@@ -14,8 +14,7 @@ import static org.mockito.internal.verification.VerificationModeFactory.times;
 import java.util.Arrays;
 import org.junit.jupiter.api.Test;
 
-class ParallelDeadlineGroupTest extends CommandTestBase
-    implements MultiCompositionTestBase<ParallelDeadlineGroup> {
+class ParallelDeadlineGroupTest extends MultiCompositionTestBase<ParallelDeadlineGroup> {
   @Test
   void parallelDeadlineScheduleTest() {
     try (CommandScheduler scheduler = new CommandScheduler()) {
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroupTest.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroupTest.java
index dd650c4bac..ea780c6216 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroupTest.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroupTest.java
@@ -16,8 +16,7 @@ import static org.mockito.Mockito.verify;
 
 import org.junit.jupiter.api.Test;
 
-class ParallelRaceGroupTest extends CommandTestBase
-    implements MultiCompositionTestBase<ParallelRaceGroup> {
+class ParallelRaceGroupTest extends MultiCompositionTestBase<ParallelRaceGroup> {
   @Test
   void parallelRaceScheduleTest() {
     try (CommandScheduler scheduler = new CommandScheduler()) {
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/RepeatCommandTest.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/RepeatCommandTest.java
index 53abdd8dc9..2aaecc6d93 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/RepeatCommandTest.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/RepeatCommandTest.java
@@ -10,8 +10,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.junit.jupiter.api.Test;
 
-class RepeatCommandTest extends CommandTestBase
-    implements SingleCompositionTestBase<RepeatCommand> {
+class RepeatCommandTest extends SingleCompositionTestBase<RepeatCommand> {
   @Test
   void callsMethodsCorrectly() {
     try (CommandScheduler scheduler = new CommandScheduler()) {
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SelectCommandTest.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SelectCommandTest.java
index 0ce3b79057..e364468186 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SelectCommandTest.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SelectCommandTest.java
@@ -13,8 +13,7 @@ import java.util.HashMap;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-class SelectCommandTest extends CommandTestBase
-    implements MultiCompositionTestBase<SelectCommand<Integer>> {
+class SelectCommandTest extends MultiCompositionTestBase<SelectCommand<Integer>> {
   @Test
   void selectCommandTest() {
     try (CommandScheduler scheduler = new CommandScheduler()) {
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SequentialCommandGroupTest.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SequentialCommandGroupTest.java
index ff578f45d4..abbc49062c 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SequentialCommandGroupTest.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SequentialCommandGroupTest.java
@@ -12,8 +12,7 @@ import static org.mockito.Mockito.verify;
 
 import org.junit.jupiter.api.Test;
 
-class SequentialCommandGroupTest extends CommandTestBase
-    implements MultiCompositionTestBase<SequentialCommandGroup> {
+class SequentialCommandGroupTest extends MultiCompositionTestBase<SequentialCommandGroup> {
   @Test
   void sequentialGroupScheduleTest() {
     try (CommandScheduler scheduler = new CommandScheduler()) {
diff --git a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SingleCompositionTestBase.java b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SingleCompositionTestBase.java
index 4e54e3ec00..a063a1de63 100644
--- a/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SingleCompositionTestBase.java
+++ b/wpilibNewCommands/src/test/java/edu/wpi/first/wpilibj2/command/SingleCompositionTestBase.java
@@ -5,17 +5,19 @@
 package edu.wpi.first.wpilibj2.command;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.EnumSource;
 import org.junit.jupiter.params.provider.ValueSource;
 
-public interface SingleCompositionTestBase<T extends Command> {
-  T composeSingle(Command member);
+public abstract class SingleCompositionTestBase<T extends Command> extends CommandTestBase {
+  abstract T composeSingle(Command member);
 
   @EnumSource(Command.InterruptionBehavior.class)
   @ParameterizedTest
-  default void interruptible(Command.InterruptionBehavior interruptionBehavior) {
+  void interruptible(Command.InterruptionBehavior interruptionBehavior) {
     var command =
         composeSingle(
             new WaitUntilCommand(() -> false).withInterruptBehavior(interruptionBehavior));
@@ -24,9 +26,38 @@ public interface SingleCompositionTestBase<T extends Command> {
 
   @ValueSource(booleans = {true, false})
   @ParameterizedTest
-  default void runWhenDisabled(boolean runsWhenDisabled) {
+  void runWhenDisabled(boolean runsWhenDisabled) {
     var command =
         composeSingle(new WaitUntilCommand(() -> false).ignoringDisable(runsWhenDisabled));
     assertEquals(runsWhenDisabled, command.runsWhenDisabled());
   }
+
+  @Test
+  void commandInOtherCompositionTest() {
+    var command = new InstantCommand();
+    new WrapperCommand(command) {};
+    assertThrows(IllegalArgumentException.class, () -> composeSingle(command));
+  }
+
+  @Test
+  void commandInMultipleCompositionsTest() {
+    var command = new InstantCommand();
+    composeSingle(command);
+    assertThrows(IllegalArgumentException.class, () -> composeSingle(command));
+  }
+
+  @Test
+  void composeThenScheduleTest() {
+    var command = new InstantCommand();
+    composeSingle(command);
+    assertThrows(
+        IllegalArgumentException.class, () -> CommandScheduler.getInstance().schedule(command));
+  }
+
+  @Test
+  void scheduleThenComposeTest() {
+    var command = new RunCommand(() -> {});
+    CommandScheduler.getInstance().schedule(command);
+    assertThrows(IllegalArgumentException.class, () -> composeSingle(command));
+  }
 }